OPAL, Wyo. – A small town in southwest Wyoming was evacuated Wednesday after an explosion and fire at a natural gas processing facility and major national pipeline hub. There were no reports of injuries.

The gas has been shut off, but people who were in Opal, about 100 miles northeast of Salt Lake City, went to an area about 3 miles outside of town as a precaution, said Lincoln County spokesman Stephen Malik. The town has about 95 residents.

“They were downwind from the plant,” said Lincoln County Sheriff Shane Johnson. “The fire was still very active, and because of the nature of the processing that goes on there, that was the call that was made for safety reasons.”

Johnson said he didn’t know when people would be allowed back into Opal.

No structures in the town were affected, and the fire was confined to the facility operated by pipeline operator Williams Partners LP, county officials said.

The explosion occurred in the plant’s cryogenic processing tower, a structure that chills unrefined natural gas to separate out impurities, but officials didn’t yet know what caused the blast.

The explosion was reported at about 2 p.m., and the fire continued to burn into the evening. Williams spokeswoman Michele Swaner said it was being allowed to burn itself out.

The gas processing plant in Opal removes carbon dioxide and other impurities from natural gas that comes from gas fields in the region. It can gather up to 1.5 billion cubic feet of gas per day, and it sends it into pipelines that go to urban centres to the east, west and south.

Williams Partners, based in Tulsa, Okla., said in a statement it has suspended collecting gas from surrounding areas and is looking for ways to resume production.

The Opal hub, where regional pipelines converge, is the principal spot where prices are set for natural gas produced from the large gas fields in western Wyoming and the San Juan Basin in Utah. The plant makes Opal perhaps best known as a regional gas-pricing hub. Government officials and industry insiders closely watch Opal hub prices to monitor trends with regional gas supply and demand.

Williams operates the Northwest Pipeline, which runs through Opal on its way to the Pacific Northwest. An explosion in March at a liquefied natural gas facility operated by Williams on the Washington-Oregon border injured five employees.

Gas from the Williams plant at Opal serves a huge number of customers from the Pacific Northwest to Southern California, the Southwest and even as far east as Ohio, said Brian Jeffries, executive director of the Wyoming Pipeline Authority.

How long the plant would be out of commission was unknown, but Jeffries said the effect won’t be as bad as if the explosion occurred during winter, when demand for natural gas increases for heating, or summer, when demand increases to generate electricity for air conditioners.

“It really is that time of year when it’s sort of least likely to impact customers,” he said.

Williams was paying to lodge Opal residents at the Little America resort in Little America, about 25 miles east of Opal, and at a Best Western in Kemmerer, about 15 miles to the west.

“We want to make sure everybody’s taken care of and they’re put up for the night if they’re not able to go back to their houses,” Swaner said.

“Since nobody’s on site, it’s going to take some time before we can begin our investigation,” Swaner said.

Renny MacKay, spokesman for Gov. Matt Mead, said investigators would look into the cause of the explosion once the site was secured.